Zzzz
58 lines
2.0 KiB
Java
58 lines
2.0 KiB
Java
package com.mzh.library.util;
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import com.mzh.library.exception.DaoException;
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import java.io.IOException;
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import java.io.InputStream;
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import java.sql.Connection;
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import java.sql.DriverManager;
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import java.sql.SQLException;
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import java.util.Properties;
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public final class JdbcUtil {
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private static final String CONFIG_FILE = "db.properties";
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private static final String DEFAULT_DRIVER = "com.mysql.cj.jdbc.Driver";
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private JdbcUtil() {
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}
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public static Connection getConnection() {
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Properties properties = loadProperties();
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String driver = properties.getProperty("db.driver", DEFAULT_DRIVER);
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String url = required(properties, "db.url");
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String username = required(properties, "db.username");
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String password = required(properties, "db.password");
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try {
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Class.forName(driver);
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return DriverManager.getConnection(url, username, password);
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} catch (ClassNotFoundException | SQLException ex) {
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throw new DaoException("Unable to open database connection", ex);
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}
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}
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private static Properties loadProperties() {
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try (InputStream inputStream = Thread.currentThread()
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.getContextClassLoader()
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.getResourceAsStream(CONFIG_FILE)) {
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if (inputStream == null) {
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throw new DaoException("Missing database configuration file: " + CONFIG_FILE, null);
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}
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Properties properties = new Properties();
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properties.load(inputStream);
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return properties;
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} catch (IOException ex) {
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throw new DaoException("Unable to read database configuration", ex);
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}
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}
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private static String required(Properties properties, String key) {
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String value = properties.getProperty(key);
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if (value == null || value.trim().isEmpty()) {
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throw new DaoException("Missing database configuration value: " + key, null);
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}
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return value.trim();
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}
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}
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